Confirmation of Hb F in Hb typing result by acid elution test

Abstract

                Thalassemia is a genetic disease commonly found in Thailand. Hemoglobin typing (Hb typing) is used for detection of thalassemia. Problems could occur such as some abnormal Hb are separated in Hb F-peak giving misdiagnosis between high Hb F condition in beta-thalassemia disease and abnormal Hb carrier. Staining of Hb F by acid elution test (AET) might help to confirm whether that in Hb F-peak was really Hb F which important in beta-thalassemia diagnosis. Objective: To use AET for Hb F staining to distinguish between Hb F and abnormal Hb eluted in Hb F-peak. Methods: The total of 302 blood samples having Hb F-peak by Hb typing analysis was stained using AET. Abnormal Hb including Hb Q-Thailand and Hb Tak were confirmed by DNA analysis. Data were analyzed for AET method to use as Hb F confirmation. Results: Hb F staining by AET had sensitivity 93.3%, specificity 100%, PPV 100% and NPV 80.0% for detection of Hb F distinguished from abnormal hemoglobin. The correlations of %Hb F from Hb F staining and Hb typing on CE and HPLC were 0.8595 and 0.8675, respectively. Conclusions: AET could be used to confirm Hb F for correct Hb typing interpretation that improved thalassemia diagnosis. The method was easy, inexpensive, no special equipment used and useful in laboratories which have only one type of Hb typing machine.